Hydraulic brake



Allg. '19, 1941.v C; L EKsERGlAN. A* 2,253,205 A HYDRAULIC BRAKE V Filed July 19, 1939 I f v fr; Y ll will Patented Aug. 19, 1941 HYDRAULIC BRAKE Carolus L. Eksergian, Detroit, Mich., assignor to Budd Wheel Company, Philadelphia, Pa., l. corporation of Pennsylvania Application July 19, 1939, serial No. 285,268

Viiillaims.

The present invention relates to brakes for vehicles, more particularly to the type known as hydraulic brakes, which are actuated by uid pressure.

More specically, the invention relates to an improved and simpliiied type of brake, having (ci. iss- 152) two cylinders each actuating both brake .shoes in opposite directions, each cylinder having an vadjusting device cooperating therewith to provide joint adjustment -of both brake shoes to the same extent.

Still more speciiically, each cylinder has a pair of opposed pistons therein, saidpistons hav.- ing inclined surfaces at their adjacent ends, and .a conical element disposed between the pistons, having means for moving it transversely of the axis of the cylinder, to vary the spacing of the'pistons when not4 subjected to the pressure of the operating iluid.

Another feature of the invention has to do with the support of the shoes directly on the pistons of the actuating cylinders', whereby the shoes are guided by the pistons, and, in turn, prevent rotation of the pistons in the cylinders.

Other objects and advantages of the invention will be evident from the present specification and the drawing accompanying the same, disclosing one embodiment of the invention.

In said drawing:

Fig. 1 is a front elevation of brake mechanism embodying the invention, one of the cylinders and the parts enclosed therein being shown in vertical longitudinal section;

Fig. 2 is a cross section through the mecha' nism, on the plane indicated by the line 2-2 of Fig. 1; .l

Fig. 3 is a fragmentary detail of a cylinder and adjacent parts partly in section on the planes indicated by the broken line 3-3 of Fig. l; and

Figs. 4 and 5 are fragmentary sectional views ing the brake pistons'.

moved intoand outyof ional ontact with the inner surface,itiresV are secured to and carried by .cylindrical 'arcuate shoes 5 each of which has a iiat, arcuate flange or web 6 extending inward from approximately its central portion. Each iiange ihas at each end a reduced, rounded abutment-1 and these abutments are received within the hollow ends l of 'the pistons 9, against which they are held by thetensile springs AIII having their ends II engaged in suitable holes I2 in the webs 8.

The backing plate I has e. central opening I3, to pass over the axle and adjacent said opening has a number of smaller holes I4, which are intended tov receive bolts. for securing the casing I to any suitable stationary portion of the vehicle, adjacent the axle; -Clips r guides I5, which may preferably be somewhat resilient, are provided to guide the shoes 5in their movements, by bear/ing against the webs or iianges 6 thereof. These clips may be bent to the shape shown in Fig. 2, and secured to the backing plate I' by iastenings I6,such as rivets while prevented positively vfrom turning by means of projecting tabs I'l received in holes I8 in the casing.

Two Vcylinders I9 are secured to the backing I plate l by any suitable means. such as the cap screws 2li threaded into bosses 2| on the cylinders, with lock washers 22 to keep the screws from loosening. Each cylinder I9 is relatively simple, and may be of uniform bore throughout its length.. Both of the cylinders may have ports 23 formed therein, which communicate with the ilttings 24, to one of which the conduit 2S is attached, to supply the pressure fluid I or actuat- The iiuid may be fed to the other cylinder through the ttings 26, one of which is provided on each cylinder. These iittings communicate with the cylinders through the bores 21, and may be connected with each other by any suitable conduit' 28, as shown in dotted lines in Fig. 2.

Each cylinder I9 contains two similar pistons 9, which are however placed back to back and have cavities 8 in their outer ends to receive the abutments 1 of the brake shoes 5. Suitable packing means, such as one or more rings 29, may 'be mounted on each` piston to provide a fluid 4tight jointwith the boren! the cylinder and nels 30, as shown, so as to keep-these ends of the pistons out of contact `with the cylinder wall.

A closure 3| which may be made of any suitable flexible material, may be seated in a groove 32 in the outersurface of each end of thecylinder, and may also be fitted closely against the ange 1 as shown at 33, thus keeping dirt and foreign matter out of the exposed endsl of the pistons and cylinders.

It will be understood that the springs I will draw the brake shoes 5 away from the brake drum, whenever there is insuiilcient fluid pressure in the cylinders to overcome said springs, and in so doing they would cause the inner ends of the pistons in each cy'linder to abut against one another, if not prevented from doing so. However,` it is desirable to provide an adjustable degree of movement of the brake shoes to adjust them initially, and subsequently for wear, and this is easily accomplished by providing an adjustable wedge 34 which moves transversely to the axis of the cylinders, between the pistons.

In order to simplify the adjusting means, the wedge 34 is preferably made conical, as shown in Figs. 2 and 3, and the inner ends of the pistons 9 are formed on a corresponding incline, to receive said cone and make adequate contact therewith. The cone 34 has a screw-threaded stem 35 secured thereto at its vertex, or integral therewith, and this stem passes out through a threaded opening 36 in the cylinder, and terminates in a flattened endv 31, to facilitate turning it by means of a suitable wrench or key. A packing washer 38 may be placed over the stem 35, and forced against the outside of the casing l by a nut 39, to prevent leakage and at the same time to lock the stem against accidental loosening in service.

The cones 34 may have central guide means,

` to control them and keep them in proper position. This may be accomplished by the bore 40 in each cone, which receives a stud 4i extending from a screw-threaded plug 42 engaged in the threaded transverse bore 43 of each cylinder I9. The said plugs may have hexagonal or other polygonal cavities 44 therein, to receive a tool for tightening or removing them. Suitable gaskets render the plugs fluid-tight.

ing the spring l which lies adjacent to the link.

At its other end, the lever 41 may have any suitable attachment means for the cable 56, such as the socket 51 at the lower end of lever 41. This cable 56 extends out from the backing plate l through a suitable guide, such as the tubular i member 58 and is attached to the emergency the backing plate I and the adjustable wedges It will be noted that while each cyunder I9 has a fitting 24 adapted to receive the fluid supply pipe 25, usuallyonly one is so connected, preferably the upper one, and the remaining fitting 24 is then closed by a plug 45, threadedly engaged therein, with a packing washer 46 toseal the joint. The plug 45 may thus serve alsas a drain plug, since it is at the lowest point of the iluid conduit, thus making it possible to drain, flush, and refill the same readily whenever necessary.

It is desirable to supplementl the hydraulic operating means by a mechanical actuating device, for emergency use. This is provided for ina-the present structure by the lever 41, having a bearing 48 ,at one end pivotally connected to the stud 49 which is integral with, or suitably secu-red to, one end of one of the flanges 6 of one of the shoes. A short distance from the stud 49, the lever 41 has a stud 50 pivotally engaged in aslot 5I in the end of-thelink 52, which link is bent up at one end as shown and provided with a bearing 53 pivotally engaging a stud 54 on the flange 6 of the adjacent endof the other shoe.

The link 52 may have a single corrugation 55 extending along the same, which serves the double purpose of stiiiening the link 52 and of clearserve also as the anchor pins taking the thrust of the shoes, depending upon the direction of rotation of the drum.

In the form of the invention shown in Figs 4 and 5, the piston, as 9 is provided centrally with a shallow slot 8' having a rounded bottom against which the rounded end 1 of the shoe bears. The slot engages the rounded transverse flat end of the shoe fairly snugly and this engagement of the shoe with the slot prevents rotation of the piston in the cylinder, and this insures that the conical wedge 34 and the correspondingly inclined end of the piston will always be maintained in their proper cooperative relation.

The operation of the brake is as follows:

When fluid under pressure is admitted into the cylinders I9, it will force apart the pistons 9 in each and thus cause the brake shoes 5 to bear outwardly against the interior of the backing plate I, thereby producing the braking effect.

The springs I0 will retract the shoes 5 when the fluid pressure is decreased sufficiently, thus releasing the brakes. In order to adjust the play between the shoes and the drum, the conical plugs or cams 34 may be moved in or out, by turning their threaded stems 35, this being readily done by use of a suitable key or wrench on the flattened end portions 31 of said stems. Each conical cam 34 may of course be adjusted independently and it may be suiiicient to provide'the adjustment on but one of the cylinders.

When for any reason the braking is to be done mechanically, a pull is exerted on the cable 56,

which will thus .move the lower end of lever 41 to the left. This will bring the stud 50 against th-e bottom of the slot'5l in the link 52, and then will cause the link to move to the left, carrying v with it the upper end of the left flange 6, while "at the same time the upper end of lever 41 will itself move to the right, carrying along the upper end of the right flange 6, so that thus the shoes 5 will b-e caused to engage the casing I. In this mechanical actuation; the shoes 5 will pivot about their lower ends, the pistons in the lower cylinder being inabutting relation with the adjustable cone anchor, since the force is applied only at-the upper end of each flange 6 of the shoes. It is clear that because of the slot 5|, there willvbe no interference between the fluid-pressure actuation and the mechanical actuation, since the brake shoes Acan thus move freely in response to the fluid actuation without affecting the emergency brake linkage in any way.

It will of course be understood that while p3; ferred forms of the device have been disclosd in great detail, this is not to be considered as in The brake I any way limiting the invention to the-specific embodiments chosen for illustration. `The scope of the invention is therefore dened in the following claims.

`I claim:

il. A brake comprising a rotary element, a pair of brake shoes adapted to be forced aaginst said element.' a relatively stationary cylinder having two pistons therein, whereby they will move in opposite directions when iiuid under pressure is admitted into the cylinder, between said pistons, means operatively connecting each piston to a corresponding one of said brake shoes, whereby such movement of the pistons will cause the shoes to be forced against the rotary brake element. meansior returning the shoes to inoperative position and manually adjustable anchor means carried by the cylinder and arranged to engage said pistons to simultaneously adjust each piston, and thereby control the return' position of said shoes. Y

2. A brake comprising a rotary element, a pair of brake shoes adapted to be forced against said element, a' pair of relatively stationary cylinders, said cylinders being spaced apart, and

Vlocated near opposite pairs of ends of the brake shoes, each cylinder havingV two pistons therein, whereby they will move in opposite directions when fluid under pressure is admitted into the cylinder, between said pistons, means operatively connecting each piston to a corresponding one of said brake shoes, whereby such movement of the pistons will cause the shoes to be forced against the rotary brake element, means for returning the shoes to inoperative position,

and manually adjustable anchor means carried by each cylinder and arranged to engage the pistons associated with said cylinder to simultaneously adjust said pistons, and thereby control the return positions of the shoes.

3. A brake comprising a rotary element, a pair of brake shoes adapted to be forced against said element, a relatively stationary `cylinder having two pistons therein, whereby they will move in opposite directions when fluid under pressure f is admitted into the cyunder, between said pistons, manuallyadjustable anchor means carried by the cylinder for spacing the inner ends of said pistons apart and limiting their return movement, and means operatively connecting' each piston to a corresponding one of said brake shoes, whereby outward movement of the pistons will cause the shoes to be forced against the rotary brake element.

4. A brake comprising a rotary element, a pair of brake shoes adapted to be forced against said element, a relatively stationary cylinder having two pistons therein, manually adjustable means carried by the cylinder for varying the' minimum spacing between the inner ends of said pistons, said adjustable means serving 4to anchor at least one of said shoes, said pistons moving in opposite directions when fluid under pressure is admitted into the cylinder, between said pistons, and means operatively connecting each piston to a. corresponding one of said brake show, whereby such movement of the pistons will cause the shoes to be forced against the rotary brake eley ment.

- ing the minimum spacing between the adjacent ends of said pistons and serving as anchor means for the shoes, and means operatively connectingl each piston to a corresponding one of said brake shoes, whereby outward movement of the pistonswill cause the shoes to be forced against the rotary brake element.

6. A brake comprising a rotary element, a pair of brake shoes adapted to be forced against said element, a relatively stationary cylinder having two spaced pistons therein, whereby they will move in opposite directions when fluid under pressure is admitted into the cylinder, between said pistons, a tapered spacing cam carried by the cylinder anddisposed between the pistons, means extending outside the cylinder for adjusting said cam, and means operatively connecting each piston to a corresponding one of said brake shoes, whereby such movement of the pistons will cause the shoes to be forced against the rotary brake element.

7. A brake comprising a rotary element, a pair of brake shoes adapted to be forced against said element, a relatively stationary cylinder having two spaced pistons therein, whereby they will move in opposite directions when fluid under pressure is admitted into the cylinder, between said pistons, a frusto-conical cam carried by the .y

cylinder and bearing against the inner .ends of said pistons, means for adjusting said cam transa versely` of the cylinder,` to vary the minimum separation of the pistons, and means operatively connecting each piston to a corresponding one of said brake shoes, whereby such movementof the pistons will cause the shoes to be forced against the rotary brake element.

8. A brake comprising a rotary element, a pair of brake shoes adapted to be forced against said i element, a pair of relatively stationary cylinders,I said cylinders being spaced apart, andlocated? near opposite pairs of ends of the brake shoes, each cylinder having two pistons therein, which will move in opposite directions when fluid under` pressure is admitted into the cylinder, between said pistons, a tapered cam carried by each cylinder and disposed 'between the pistons of each pair, said cam having an adjusting stem extending beyond the cylinder, so as to be accessible from outside, for varying the minimum spacing between the inner ends of the pistons, and means operatively connecting each piston Vtoa corresponding one of said brake shoes,

whereby such movement of the pistons will cause the shoes to be forced against the rotary brake element. 9. A brake comprising a pair of arcuate brake shoes, a brake actuating cylinder disposed between the adjacent ends of said shoes, pistons in said cylinder one for engagement with each shoe, manually adjusted cam means carried by the cylinder and cooperating with the correspondingly cam faced inner faces of said pistons for simultaneously adjusting them outwardly and serving as anchoring means for 4the shoes, the engagement between each piston audits associated shoe preventing rotation of the piston in the cylinder to maintain said cam surfaces in proper alignment.

cAaoLUs L. EKSERGIAN. 

